The present disclosure relates to a system and method for preventing a water tank from overheating. The water tank might be the type which is used in a water heating system as well as a brewer. The disclosure is not intended to be limited to these areas but, is considered to be applicable to a variety of water heating devices which will benefit from the teachings of this disclosure.
Many forms of brewing apparatus have been developed which use a device for heating water. In some of the apparatus, the water heating device is in the form of a tank or reservoir which includes a heating element or device either inside the tank of external to the tank for heating water in the tank. Water is introduced into the tank for heating and dispensing over a beverage brewing substance. Alternatively, water is dispensed into the tank for heating and retained in the tank for subsequent dispensing.
A concern in such a water heating system is to prevent the water from overheating. Generally, depending on altitude, water will boil at a temperature of approximately 212° F. If the water is too hot, it will tend to boil and vaporize. In a situation where heated water is used to brew a beverage it may be undesirable to boil the water because the brewing temperature may be too high and the boiling action will reduce the quantity of water which is available for brewing. In other words, if the user of such a brewing apparatus does not want to use boiling water to brew a beverage, but rather a water temperature which is below boiling, such as 190-205° F.
Some prior art devices control the temperature of the heated water by use of a bimetallic thermostat. Such thermostatic devices are known in the art and available to one of ordinary skill in the art for this purpose. By way of example, and not limitation, the bi-metallic thermostat opens when the temperature drops below a pre-determined lower range thereby signaling to a controller that the corresponding heating element should be energized to heat the water in the tank. When the upper level temperature is detected, the bi-metallic thermostatic sensor closes, closing the circuit to the heating element and shutting off the heating element. By opening and closing the bi-metallic circuit, the heating element is turned on and off to controllably add energy to the water.
In some environments, it may be desirable to include a backup system for detecting the tank heating and preventing overheating in the event of the failure of the first thermostatic sensor. For example, Underwriters Laboratory, UL, may require backup thermostatic sensors in some situations. In order to satisfy the UL certification requirements, such a backup sensor or system may need to be provided.
Additional features and embodiments will become apparent to those skilled in the art upon consideration of the following detailed description of drawings.